Backstage passes came into existence around the time roadies became Road Crew.
In the old days having long hair, a scruffy appearance and saying "I'm with the bandĚ" was enough to gain access to all areas.

But security tightened and a plastic lapel conference badge with sticky dymo label strips was the cool accessory to wear and impress. Shortly afterwards, the stick on pass, followed by the laminate which were issued to touring staff and guests.

One method of tightening security were to have your name or your photo on passes assigned to touring personnel. Queen touring staff sometimes had a number assigned to them which would be on your pass, luggage tags and hotel room list.